It is said that the lower price end of cameras have a less quality of glass, which in turn is less sharp. ( Better quality glass = better quality images )
Does this mean that a Canon 6D is sharper with better quality images than a 60D
And thus, a 60D likewise with a 600D ??

The question seems difficult, if not impossible, to answer because it is asking for a comparison of different technologies - the glass is in the lenses, and presumably the same quality lens could be fitted to the three different bodies. The comparison is not then about the glass but about the combined performance of the sensor, electronics and programming within those different bodies. Or then another interesting question might be - does a higher quality lens on the 600D give sharper images than a lower quality lens on a 6D?

I have a 650D Canon but would like to upgrade to a full frame.
I like to take bird and wildlife shots but am not quite sure which way to go.
9 out of 10 shots seem a little on the soft side to me. I want to get the focus spot on when zooming in

Johnny, to eliminate, possible shake, etc, use a tripod, fast shutter speed, take a pic of text, at your average distance/settings, evaluate, and go from there. I went from 6.5M Pixels, to 14M, am using the same lens, Tamron, and see no difference really. Any prints I have made, are A3, I am happy with results. Ed.

(Nov 9, 2014, 07:07)johnytrout Wrote: I have a 650D Canon but would like to upgrade to a full frame.
I like to take bird and wildlife shots but am not quite sure which way to go.
9 out of 10 shots seem a little on the soft side to me. I want to get the focus spot on when zooming in

Johny, have you given thought to the lenses. For example, to get the same magnification as a 300mm lens on your 650D would give, e.g. when out photographing birds, you would need to buy a 480mm telephoto lens for a full-frame camera. That would entail a considerable extra cost, assuming that you want good quality, even if you are using those focal lengths in third-party zoom lenses.

Thank you for that information Philip.
So a full frame will decrease the magnification on the lenses that I have now
Nobody has ever told me that before. Well I live and learn.
So what would be the equivalent of my 400mm on a full frame??

I think Canon usually have a 1.6x crop factor, so multiply by 1.6. Therefore, you would need a 640mm lens on a full-frame camera to give the same field of view you see with a 400mm on the 650D. I don't know Canon mounts but, even if your 400mm would fit, whether it would work depends on the image circle produced by your lens - if it is designed for your size camera (APS-C) it will probably vignette (produce very dark corners) on full-frame.

If my memory serves me correctly, with the Canon system the EF series of lenses (full frame) will fit on the cropped sensor models of body. However the EF-S series of lenses (the cropped sensor lenses) will not fit on the full frame bodies. In saying that, it might well be the other way around!! I also believe that it is literally that they won't fit. This is one of many reasons I went the Nikon route when 'going digital', as most of the Nikon lenses produced post 1975 will fit on any Nikon body and still work, albeit at a reduced resolution and functionality in some instances.

Also, please bare in mind that I could be completely wrong and probably am.

Canon full frame lenses fit the cropped frame bodies - but not the other way round.

Canon cropped frame bodies have a white spot and a red spot on the lens mount. Lenses designed for full frame have a red spot and fit any camera with a red spot (full frame and cropped). Lenses for cropped frame cameras only are smaller, lighter and have a white spot.

In summary. Cropped frame Canon cameras take both types of lens, full frame cameras only take the red spot lenses

OK, So let me get this straight.
I have a Canon DSLR EOS 650D camera which is cropped to 1.6 (not full frame)
My kit lens 18-55mm has a white square dot which means its a EFS that will not fit a full frame. Not too bothered by that one!

Also a zoom 75-300 red dot EF and a EF 100-400mm f/4.5-5.6L IS USM - Telephoto zoom red dot ......... they will both fit onto a full frame camera.
Thank you for enlightening me

But remember that the subject of your image will not be magnified as much when using the lens on a full-frame camera. If you consider it in terms of the maximum magnification of the usual view (i.e. normal vision, or when using a standard lens on the camera), the 400 mm lens would give you about 13x on the 650D, but only about 8x on a full-frame camera.

The lens advantages of full-frame sensors work in the opposite direction - an even more wide angle effect from short focal length lenses - to benefit subjects such as landscape and internal/external architectural shots. Their other main advantage is lower noise at high ISO values - useful if a lot of work is in very low light (although even then, modern APS-C cameras can produce good results up to ISO 3200+).

If your main interest is wildlife, whether from a distance or in macro shots, the magnification advantages of an APS-C sensor camera would seem to suggest that your upgrade path (if the 650D is not up to the job) should be a better APS-C body rather than full-frame.

Your Flickr stream shows many very good wildlife photos from your present camera sensor format so, if you were to upgrade to a better APS-C for your wildlife shots, you might consider adding a good prime lens for portraits, e.g. Sigma 50mm f/1.4 EX DG HSM - equivalent to 80mm on APS-C.

The 650D was a great camera for many reasons but one lens I had just wasn't sharp. After LOTS of reading, then testing I found the lens suffered from forward focus, which meant it was focusing in front of the auto focus point. This can really matter with a long lens as depth field can be very small. With the 650D there was only one thing that could be done - return the lens to Sigma, preferably with my body for adjustment of the lens to focus correctly. And include a fairly chunky fee + insured postage etc etc.

So after more investigation I upgraded to the 7d. A different build quality camera altogether. It has mag alloy body frame instead of plastic. This can make a difference - image quality is not only optics and electronics - the distance between the lens mount and the sensor plane is fundamental also. With a metal body it can be manufactured and maintained more readily than a plastic one.
But most importantly, the 7D had micro adjustment for auto focus. This meant that any lens which moderately front or rear focuses can be adjusted withing the body on an lens by lens basis by the user.
Also the 7D could use my 2 favorite EF-S lenses, the 10-20 and 18-200.
Why did I later move onto a 6D? A relative dropped and damaged the 7D. And after the repair it was just fine but for me it was never the same. I had also recently come back from my holiday of a lifetime and there were lots of photos where i asked the perennial question 'where was that taken'. Also I was becoming more interested in natural low light photography. The 6D fitted the bill because of the full frame sensor, micro focus adjustment, on-board GPS, and also on-board wifi.
Ignoring everything else, whats the advantage of full frame when the pixel count is similar? If a sensor is 20Mpx the resolution is the same whether the sensor is full frame, 1.6x crop, or even a modern top-end phone?
The BIG difference is the pixel size. On a full size sensor the pixels are almost twice the size as a cropped sensor. In low light and/ or high ISO it is significantly more sensitive to light, the effect of which is a lot less noise. Just consider the sizes:
full frame 36x24mm, area 864
cropped 23x15mm, area 346 (typical
so 36:23 is about 1.6x crop but area is over twice (so pixel size/area is similarly so.

cropped body:
* smaller and lighter
* can use EF or EF-S lenses
* A given lens is 60% 'longer zoom' 400mm becomes 640mm
* EF-S lenses are lighter than full frame lenses so less weight and bulk to carry
* To cover a given focal length range (eg 10 - 600) will require significantly less lenses, cost, weight etc.
* shutter is physically smaller so often has higher burst shutter rate and sometimes higher max speed.

Full frame
* super low light image quality (signal to noise ratio of large pixels) long exposure and/or high ISO
* EF lenses have smaller zoom range so typically the optical quality is less prone to distortion such a chromatic aberration, lack of corner sharpness etc

There are other differences of course but they are not necessarily full vs. cropped body specific, and naturally if you wait for the next release of any given body it will be better and will leapfrog the other models/ oposition (ain't life like that from phones, to cars to cameras to everything

To look at my own list why did I get a 6D at the time? From my perspective I now find that with the body and lenses I have,any problems with an image can clearly be seen to be mine - either technique, composition, or process they are not down to the kit that's for sure. Also, as an very enthusiastic amateur, because I wanted to and I could
What would I do now? with the lenses I had I would be very interested in the 7Dmk II particularly if wildlife/ sports photographer

must mention forward or back focus is not a Sigma thing - I had/have Sigma lenses which are superb. The more you push the equipment the more likely manufacturing and design tolerances could be exposed. Also, the fact that Canon and Nikon both include micro focus adjustment on their more advance cameras confirm to me that it is not a 'Fit for Purpose' issue.

Speaking entirely for myself, when i had the 650D I tended to use Program mode, all focusing points, and auto ISO, which worked well most of the time and the computer did most of the work to prevent glaring mistakes on focus and exposure.

As I became more knowledgeable/picky/competent/pedantic (select your own preference) I wanted to do more myself so now tend to use Aperture or Time, single focus point, and either auto or manual ISO as I think best.

It is universally advised by experts (not amateurs like me) that the eyes must be sharp. At that range on a large animal that is less than the difference between the eyes and the nose tip. a 3cm focusing error - human or camera just misses.

Here are 2 of my favourites which I think show what I mean:

full image

7D, Sigma 120-400 at 160mm 1/500 f4 ISO 1000, in shade, single focus point on the eye, hand held, range about 4m so DoF about +/- 6". Note on the 100% crop the eye is sharp as is the ear and whiskers, but see how the back ear is out of focus. Wouldn't look the same if back ear not eye was in focus

Also full image

7D, Sigma 120-400 at 350mm about 10m I recall, 1/500, f8, ISO 3200 hand held, nearly dusk. On the 100% crop the eye is sharp but there is load of noise - not apparent on a 7x5 print but certainly shows up on an A3+

So we pay our money and take our choice I guess, but returning to John's original question and having looked at his flicker pages, there is some pretty impressive stuff there. I particularly liked many of the birds in flight (which I find difficult) and close ups - which just goes to show that expensive kit isn't everything - an eye for a picture, good technique, subject knowledge, patience have a little bit to play also

you're correct Ed, the electronics of the camera operates the lens motor to bring it into focus. Unfortunately for a given motor movement the lens does not end up correctly focused and stops before or after (front/ back focused.) In very rare cases it is the camera body - easily found out if every lens focuses incorectly by the same amount in the same direction.

* Easy enough to do a rough check without fancy stuff.
* Use a largest aperture for minimum D0F;
* suggested to be about 50x distant so with 50mm lens put camera at 2.5m;
* use a target with good contrast and good focus point (for wuick test middle letter of car number plate is not bad);
*the target should be about 45 deg to line of sight;
* use single focus point on camera;

check the resulting image on a PC (camera screen is too small.) the fall off of focus should be even in front and behind the focus point. If ists sharper to the front or back then you may have front of back focus. Its on a lens by lens basis so if you suspect a problem then a little bit more effort and precise target is needed to assess and adjust. Also need to use several exposures to check it wasn't a one-off.

Since I found out about it I have checked every lens I intended to purchase. Saved me grief after the event on 2 occasions. Contrary to what some may imagine I'm not at all obsessive about it - got caught once, and now regard it as part of a comprehensive 'test drive' before I shell out my hard-earned spondoolies - especially as lenses don't often fall into the cheap category and a week's average wage doesn't necessarily buy much of one.